Contact structures

ABSTRACT

An internal static mixing system such as a disperser of mesh wire or expanded metal co-knit with a multi filament material selected from inert polymers, catalytic polymers, catalytic metals or mixtures in combination with a vertical reactor having a reaction zone and the disperser disposed in said reaction zone, particularly for carrying out paraffin alkylation using acid catalyst is disclosed. The wire mesh provides the structural integrity of the system as well as the open space required in reactors for the movement of vapors and liquids though the system. The disperser may be in sheets, bundles or bales or positioned within a frame.

This is continuation of application Ser. No. 10/219,653 filed Aug. 15,2002, now abandoned, which claims the benefit of U.S. ProvisionalApplication No. 60/323,227 filed Sep. 19, 2001 and U.S. ProvisionalApplication No. 60/334,560 filed Nov. 30, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to reaction contact structures for use asinternal packing for reactors which promote static mixing of reactioncomponents.

2. Related Information

The common objective of most alkylation processes is to bring isoalkanes(or aromatics) and light olefins into intimate contact with an acidcatalyst to produce an alkylation product. In the petroleum refiningindustry, acid catalyzed alkylation of aliphatic hydrocarbons witholefinic hydrocarbons is a well known process. Alkylation is thereaction of a paraffin, usually isoparaffins, with an olefin in thepresence of a strong acid which produces paraffins, e.g., of higheroctane number than the starting materials and which boil in range ofgasolines. In petroleum refining the reaction is generally the reactionof a C₃ to C₅ olefin with isobutane.

In refining alkylations, hydrofluoric or sulfuric acid catalysts aremost widely used under low temperature conditions. Low temperature orcold acid processes are favored because side reactions are minimized. Inthe traditional process the reaction is carried out in a reactor wherethe hydrocarbon reactants are dispersed into a continuous acid phase.

Although this process has not been environmentally friendly and ishazardous to operate, no other process has been as efficient and itcontinues to be the major method of alkylation for octane enhancementthroughout the world. In view of the fact that the cold acid processwill continue to be the process of choice, various proposals have beenmade to improve and enhance the reaction and, to some extent, moderatethe undesirable effects.

U.S. Pat. No. 5,220,095 disclosed the use of particulate polar contactmaterial and fluorinated sulfuric acid for the alkylation.

U.S. Pat. Nos. 5,420,093 and 5,444,175 sought to combine the particulatecontact material and the catalyst by impregnating a mineral or organicsupport particulate with sulfuric acid.

Various static systems have been proposed for contacting liquid/liquidreactants, for example, U.S. Pat. Nos. 3,496,996; 3,839,487; 2,091,917;and 2,472,578. However, the most widely used method of mixing catalystand reactants is the use of various arrangements of blades, paddles,impellers and the like that vigorously agitate and blend the componentstogether, for example see U.S. Pat. Nos. 3,759,318; 4,075,258; and5,785,933.

The present application presents a significant advance in the technologyrelating to alkylation and, in particular, to petroleum refiningparaffin alkylation by providing both an effective method for thealkylation, novel olefinic feed and an apparatus for obtaining a highdegree of contact between the liquid catalyst and the fluid reactantswithout mechanical agitation thereby eliminating shaft seals, reducingcosts and improving acid product separation.

SUMMARY OF THE INVENTION

Briefly, the present invention is an internal static mixing systemcomprising the combination of a vertical reactor having a reaction zoneand the disperser disposed in said reaction zone, particularly forcarrying out paraffin alkylation using an acid catalyst. A preferreddisperser comprises mesh wire with a multi filament component orexpanded metal intertwined with a multi filament component, said multifilament selected from inert polymers, catalytic polymers, catalyticmetals, the compositions of catalytic metals or mixtures thereof. Thewire mesh provides the structural integrity of the system as well as theopen space required in reactors for the movement of vapors and liquidsthough the system. The disperser may be comprised of sheets, bundles orbales of the co-knit wire and the multi filament component. The systemmay also comprise the co-knit wire and multi filaments within a frame.The reaction zone may comprise the entire column or a portion thereof.The present dispersers achieve radial dispersion of the fluid orfluidized materials in the reactor.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic representation of an apparatus in which analkylation process may be carried out using the present static internalmixing system.

FIG. 2 is a schematic representation of the combination of the presentinternal static mixing system in a reaction zone in a down flow reactor.

FIG. 3 is an enlarged view (approximately 200%) of a section of aco-knit wire and multi filament material.

DETAILED DESCRIPTION OF THE INVENTION

Preferably, the disperser comprises a conventional liquid-liquidcoalescer of a type which is operative for coalescing vaporized liquids.These are commonly known as “mist eliminators” or “demisters”, however,in the present invention the element functions to disperse the fluidmaterials in the reactor for better contact. A suitable dispersercomprises a mesh such as a co-knit wire and fiberglass mesh. Forexample, it has been found that a 90 needle tubular co-knit mesh of wireand multi filament fiberglass such as manufactured by Amistco SeparationProducts, Inc. of Alvin, Tex., can be effectively utilized, however, itwill be understood that various other materials such as co-knit wire andmulti filament TEFLON (trademark of E. I. du Pont de Nemours & Co. fortetrafluoroethylene), steel wool, polypropylene, PVDF, polyester orvarious other co-knit materials can also be effectively utilized in theapparatus. Various wire screen type packings may be employed where thescreens are woven rather than knitted. Other acceptable dispersersinclude perforated sheets and expanded metals, open flow cross channelstructures which are co-woven with fiberglass or other materials such aspolymers co-knit with the wire mesh expanded or perforated sheets.Various wire screen type packings may be employed where the screens arewoven rather than knitted.

In one aspect of the present invention novel dispersers comprise acatalytic multi filament component. In one embodiment the dispersercomprises mesh wire co-knit with a multi filament component or expandedmetal intertwined with a multi filament component, said multi filamentselected from inert polymers, catalytic polymers, catalytic metals ormixtures thereof. The multi filament catalytic material may be polymers,such as sulfonated vinyl resin (e.g., Amberlyst) and catalytic metalssuch as Ni, Pt, Co, Mo, Ag. There may be up to 100 or more multifilaments intertwined with the knitted wire or expanded metal. Thecatalytic metal filaments are generally of higher denier because oftheir greater density. The catalytic metal multi filaments aredistinguishable from the knitted wire by their fineness of the filamentswhich greatly contributes to the catalytic aspect of the structures.

The disperser comprises at least 50 volume % open space up to about 97volume % open space. Dispersers are position within the reaction zone inthe reactor. Thus, for example, the multi filament component and thestructural element, e.g., knit wire, should comprise about 3 volume % toabout 50 volume % of the total disperser, the remainder being openspace.

Suitable dispersers include structured catalytic distillation packingswhich are intended to hold particulate catalysts, or structureddistillation packings composed of a catalytically active material, suchas that disclosed in U.S. Pat. No. 5,730,843 which is incorporatedherein in its entirety and which discloses structures that have a rigidframe made of two substantially vertical duplicate grids spaced apartand held rigid by a plurality of substantially horizontal rigid membersand a plurality of substantially horizontal wire mesh tubes mounted tothe grids to form a plurality of fluid pathways among the tubes, saidtubes being empty or containing catalytic or non catalytic materials;and structured packings which are catalytically inert which aretypically constructed of corrugated metal bent at various angles, wiremesh which is crimped, or grids which are horizontally stacked one ontop of the other, such as disclosed in U.S. Pat. No. 6,000,685 which isincorporated herein in its entirety and which discloses contactstructures comprising a plurality of sheets of wire mesh formed into veeshaped corrugations having flats between the vees, said plurality ofsheets being of substantially uniform size having the peaks oriented inthe same direction and substantially in alignment, said sheets beingseparated by a plurality of rigid members oriented normally to and saidresting upon said vees.

Other suitable dispersers include: (A) random or dumped distillationpackings which are: catalytically inert dumped packings contain highervoid fraction and maintain a relatively large surface area, such as,Berl Saddles (Ceramic), Raschig Rings (Ceramic), Raschig Rings (Steel),Pall rings (Metal), Pall rings (Plastic, e.g. polypropylene) and thelike and catalytically active random packings which contain at least onecatalytically active ingredient, such as Ag, Rh, Pd, Ni, Cr, Cu, Zn, Pt,Tu, Ru, Co, Ti, Au, Mo, V, and Fe as well as impregnated components sucha metal-chelate complexes, acids such as phosphoric acid, or bonded,inorganic, powdered materials with catalytic activity; and (B) monolithswhich are catalytically inert or active which are structures containingmultiple, independent, vertical channels and may be constructed ofvarious materials such as plastic, ceramic, or metals, in which thechannels are typically square; however, other geometries could beutilized, being used as such are coated with catalytic materials.

The present internal static mixing system has been useful in a processfor the alkylation of isoparaffin with olefin or olefin precursorcomprising contacting a fluid system comprising acid catalyst, isoalkaneand olefin in concurrent flow, preferably downflow into contact in areaction zone with present system under conditions of temperature andpressure to react said isoparaffin and said olefin to produce analkylate product. Preferably, the fluid system comprises a liquid and ismaintained at about its boiling point in the reaction zone. The olefinprecursor is an oligomer of one or more tertiary olefins such as thedimer, trimer, etc. of isobutene or a material which corresponds to saidoligomer.

The reaction of oligomer of tertiary olefins with isoalkanes is on amolar basis with the constituent tertiary olefins of the oligomer ratherthan the oligomers. The alkylate product corresponds to the reaction ofthe tertiary olefin and isoalkanes.

For the purpose of illustration and not a limitation of the process, itis believed that instead of the expected reaction between the oligomerand the isoalkane, the oligomer is cracked into its olefin componentswhich react with the isoalkane on a molar basis:

1) diisobutene+2 isobutane→2 isooctane (2,2,4-trimethyl pentane)

2) triisobutene+3 isobutane→3 isooctane (2,2,4-trimethyl pentane)

The conventional view had been that the product of (1) would be a C₁₂alkane and the product of (2) would be a C₁₆ alkane; whereas the productof reactions (1) and (2) is the same and is indistinguishable from aconventional cold acid alkylation product of the reaction:

3) 2 butene-2+2 isobutane→2 isooctane

4) 3 butene-2+3 isobutane→3 isooctane

Although acid alkylations are extremely exothermic and requiresubstantial refrigeration to maintain the reaction temperature inoptimum range to prevent side reactions, the present reaction of theoligomers with the isoalkane to produce the alkylate in the same yieldsrequired less refrigeration making the process less expensive for thesame yield of useful product.

One particular method of producing oligomer is that carried out in acatalytic distillation, for example, units formerly used to produce MTBEcan readily be converted to producing oligomer merely by changing thefeed to the reactor since the same catalyst serves both reactions.

Preferably, the oligomer comprises C₈ to C₁₆ olefins corresponding tooligomer prepared from C₃ to C₅ olefin. In a preferred embodiment theoligomer has 8 to 16 carbon atoms and corresponds to oligomer which isprepared from or are oligomers prepared from C₄ to C₅ olefins.

The widest use of the paraffin alkylation is for the preparation of a C₈gasoline component. The feed to this process is usually normal buteneand tertiary butane contained in a “cold acid” reaction usually withsulfuric acid or HF. The normal butene (butene-2, for example) is acomponent of light naphtha along with normal butane, isobutane andtertiary butene. The separation of the normal butene from the isobutenecan be effected by fractionation with difficulty because of their closeboiling points. A preferred way to separate these olefin isomers orthose of the C₅ analogs is to react the more reactive tertiary olefin toform a heavier product which is easily separated from the normal olefinsby fractionation.

Heretofore, the tertiary olefin was reacted with a lower alcohol such asmethanol or ethanol to form ethers, such as methyl tertiary butyl ether(MTBE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether(TAME) which have been used as gasoline octane improvers but are beingphased out because of health concerns.

The oligomerization of the tertiary olefin is also a preferred reactionwhen carried out on a naphtha stream with the separation of normalolefin being easily achieved by fractionation from the heavier (higherboiling) oligomers (mainly dimer and trimer). The oligomers may be usedas gasoline components but there are limits to the amount of olefinmaterial desirable or allowed in gasoline and it is frequently necessaryto hydrogenate the oligomers for use in gasoline. The most desirablecomponent for gasoline blending is C₈, e.g., isooctane (2,2,4 trimethylpentane).

The oligomer may be cracked back to the original tertiary olefins andused in cold reaction. However, it has been found that it is notnecessary to crack the oligomer which may constitute the olefin feed tocold acid reaction with the alkane or may be a co-fed with mono olefins.As noted above the result is the same product as the mono olefin alonewith the additional benefit of a less exothermic overall reactionrequiring less refrigeration and, hence, a lower energy cost for thealkylation.

The oligomerization process produces a heat of reaction that does notrequire the magnitude of heat removal as in the cold acid process. Infact, when the oligomerization is carried out in a catalyticdistillation type reaction, the heat of reaction is removed as boilup,which in this type of reaction is the lower boiling mono olefins andalkanes which are being separated from the oligomer. Thus, even thoughthere is heat produced in the oligomerization it is of no cost to theproduction of the gasoline since it is used in the fractionation, andthe operating cost of the alkylation unit is reduced by the use ofoligomer to replace some or all of the conventional short chain olefin.

In a preferred embodiment of the alkylation process, a light naphthastream comprising normal and tertiary olefins is contacted with acidresin catalyst under oligomerization conditions to preferentially reacta portion of the tertiary olefins with themselves to form oligomers, andfeeding said oligomers to an alkylation zone with an isoalkane in thepresence of an acid alkylation catalyst to produce an alkylation productcomprising the alkylate of said tertiary olefin and said isoalkane.

The oligomerization may be carried out in a partial liquid phase in thepresence of an acid cation resin catalyst either in straight pass typereaction or in a catalytic distillation reaction where there is both avapor and liquid phase and a concurrent reaction/fractionation.Preferably, the feed is a C₄-C₅, C₄ or C₅ light naphtha cut. Thetertiary olefins may include isobutene, and isoamylenes and are morereactive than the normal olefin isomers and are preferentiallyoligomerized. The primary oligomer products are dimers and trimers. Theisoalkanes preferably comprise isobutane, isopentane or mixturesthereof.

When a straight pass reactor is used, such as that disclosed in U.S.Pat. Nos. 4,313,016; 4,540,839; 5,003,124; and 6,335,473, the entireeffluent comprising the oligomer, normal olefins and isoalkanes may befed to an acid alkylation reaction. The normal alkanes are inert underthe conditions of the alkylation. Under alkylation conditions theisoalkane reacts with the normal olefin to form alkylate product andwith the individual constituent olefins of the oligomers to form thealkylate product. The implication of the result of the present processis that the oligomers are dissociated or in some manner make theirconstituent olefins available for reaction with isoalkanes. Thus, thereaction will produce:

1) isobutene oligomer+isobutane→isooctane;

2) isobutene oligomer+isopentane→branched C₉ alkanes;

3) isoamylene oligomer+isobutane→branched C₉ alkanes;

4) isoamylene oligomer+isopentane→branched C₁₀ alkanes;

whereas it would have been expected that reaction 1) would produce atleast or mostly C₁₂ alkanes, reaction 2) would produce at least ormostly C₁₃ alkanes, reaction 3) would produce at least or mostly C₁₄alkanes, and reaction 4) would produce at least or mostly C₁₅ alkanes.

When a catalytic distillation reaction such as that disclosed in U.S.Pat. Nos. 4,242,530 or 4,375,576 is employed for the oligomerization,the oligomer is separated from the lower boiling normal olefins andalkanes in the reaction product by concurrent fractionation. Thestreams, normal olefins and alkanes (overheads) and oligomers (bottoms),may be united or individually fed to the alkylation or may be usedindividually with at least the oligomer being feed to the alkylation.

The present invention offers an improved contacting apparatus andprocess for producing and separating an alkylate product using sulfuricacid as catalyst. This same or similar device may also be used withother acids or acid mixtures.

The process preferably employs a downflow reactor packed with contactinginternals or packing material (which may be inert or catalytic) throughwhich passes a concurrent multi phase mixture of sulfuric acid,hydrocarbon solvent and reactants at the boiling point of the system.The system comprises a hydrocarbon phase and an acid/hydrocarbonemulsion phase. A significant amount of sulfuric acid is held up on thepacking. Reaction is believed to take place between the descendinghydrocarbon phase and the sulfuric acid dispersed on the packing. Olefincontinuously dissolves into the acid phase and alkylate product iscontinuously extracted into the hydrocarbon phase. Adjusting thepressure and hydrocarbon composition controls the boiling pointtemperature. The reactor is preferentially operated vapor continuous butmay also be operated liquid continuous. The pressure is preferentiallyhigher at the top of the reactor than at the bottom. Adjusting the flowrates and the degree of vaporization controls the pressure drop acrossthe reactor. Multiple injection of olefin is preferred. The type ofpacking also influences the pressure drop due to the acid phase hold-up.The product mixture before fractionation is the preferred circulatingsolvent. The acid emulsion separates rapidly from the hydrocarbon liquidand is normally recycled with only a few minutes residence time in thebottom phase separator. Because the products are in essence rapidlyextracted from the acid phase (emulsion), the reaction and/or emulsionpromoters used in conventional sulfuric acid alkylation processes may beadded without the usual concern for breaking the emulsion. The processmay be described as hydrocarbon continuous as opposed to acidcontinuous.

The hydrocarbon feedstock undergoing alkylation is provided to thereaction zone in a continuous hydrocarbon phase containing effectiveamounts of olefinic and isoparaffinic starting materials which aresufficient for forming an alkylate product. The olefin:isoparaffin moleratio in the total reactor feed should range from about 1:1.5 to about1:30, and preferably from about 1:5 to about 1:15. Lowerolefin:isoparaffin ratios may also be used.

The olefin component should preferably contain 2 to 16 carbon atoms andthe isoparaffin component should preferably contain 4 to 12 carbonatoms. Representative examples of suitable isoparaffins includeisobutane, isopentane, 3-methylhexane, 2-methylhexane,2,3-dimethylbutane and 2,4-dimethylhexane. Representative examples ofsuitable olefins include butene-2, isobutylene, butene-1, propylene,pentenes, ethylene, hexene, octene, and heptene, merely to name a fewand as described above may be oligomers of these olefins.

In the fluid process the system uses hydrofluoric or sulfuric acidcatalysts under relatively low temperature conditions. For example, thesulfuric acid alkylation reaction is particularly sensitive totemperature with low temperatures being favored in order to minimize theside reaction of olefin polymerization. Petroleum refinery technologyfavors alkylation over polymerization because larger quantities ofhigher octane products can be produced per available light chainolefins. Acid strength in these liquid acid catalyzed alkylationprocesses is preferably maintained at 88 to 94% by weight using thecontinuous addition of fresh acid and the continuous withdrawal of spentacid. Other acids such as solid phosphoric acid may be used bysupporting the catalysts within or on the packing material.

Preferably, the process should incorporate relative amounts of acid andhydrocarbon fed to the top of the reactor in a volumetric ratio rangingfrom about 0.01:1 to about 2:1, and more preferably in a ratio rangingfrom about 0.05:1 to about 0.5:1. In the most preferred embodiment, theratio of acid to hydrocarbon should range from about 0.1:1 to about0.3:1.

Additionally, the dispersion of the acid into the reaction zone shouldoccur while maintaining the reactor vessel at a temperature ranging fromabout 0° F. to about 200° F., and more preferably from about 35° F. toabout 130° F. Similarly, the pressure of the reactor vessel should bemaintained at a level ranging from about 0.5 ATM to about 50 ATM, andmore preferably from about 0.5 ATM to about 20 ATM. Most preferably, thereactor temperature should be maintained within a range from about 40°F. to about 110° F. and the reactor pressure should be maintained withina range from about 0.5 ATM to about 5 ATM.

In general, the particular operating conditions used in the process willdepend to some degree upon the specific alkylation reaction beingperformed. Process conditions such as temperature, pressure and spacevelocity as well as the molar ratio of the reactants will affect thecharacteristics of the resulting alkylate product and may be adjusted inaccordance with parameters known to those skilled in the art.

An advantage of operating at the boiling point of the present reactionsystem is that there is some evaporation which aids in dissipating theheat of reaction and making the temperature of the incoming materialscloser to that of the materials leaving the reactor as in an isothermalreaction.

Once the alkylation reaction has gone to completion, the reactionmixture is transferred to a suitable separation vessel where thehydrocarbon phase containing the alkylate product and any unreactedreactants is separated from the acid. Since the typical density for thehydrocarbon phase ranges from about 0.6 g/cc to about 0.8 g/cc and sincedensities for the acid generally fall within the ranges of about 0.9g/cc to about 2.0 g/cc, the two phases are readily separable byconventional gravity settlers. Suitable gravitational separators includedecanters. Hydrocyclones, which separate by density difference, are alsosuitable.

One alkylation embodiment is shown in the FIG. 1 which is a simplifiedschematic representation of the apparatus and flow of the process. Suchitems as valves, reboilers, pumps, etc., have been omitted.

The reactor 10 is shown containing a disperser mesh 40. The feed to thereactor comprises an olefin fed via line 12 such as n-butene and anisoparaffin (e.g., isobutane) fed via line 14 through line 52.Preferably a portion of the olefin is fed along the reactor via lines 16a, 16 b, and 16 c. A liquid acid catalyst such as H₂SO₄ is fed via line56 and make-up acid may be supplied through line 38. The hydrocarbonreactants are fed to the reactor which is preferably a generallycylindrical column via line 58 and through appropriate dispersing means(not shown) into the disperser mesh 40, for example, a co-knit wire andfiberglass mesh.

The hydrocarbon reactants and non reactive hydrocarbons (e.g., normalbutane) are intimately contacted with the acid catalyst as thealkylation proceeds. The reaction is exothermic. The pressure as well asthe quantities of reactants are adjusted to keep the system componentsat the boiling point but partially in the liquid phase as the systemcomponents pass down flow through the reactor in mixed vapor\liquidphase and out through line 18 into decanter 30. In the decanter thesystem components separate into an acid phase 46 containing thecatalyst, a hydrocarbon phase 42 containing the alkylate, unreactedolefin and unreacted isoparaffin, and non reactive hydrocarbons and avapor phase 44 which may contain some of each of the components and anylighter hydrocarbon components which are removed from the system vialine 50 for further handling as appropriate.

Most of the acid phase is recycled via line 24 and 56 into the reactor.Make-up acid may be added via line 38 and build-up spent acid removedvia line 48.

The hydrocarbon liquid phase is removed via line 22 with a portionrecycled to the top of the reactor via line 28. The remainder ofhydrocarbon phase is fed to distillation column 20 via line 26 where itis fractionated. Normal butane, if present in the feed, can be removedvia line 36 and the alkylate product is removed via line 34. Theoverheads 32 are primarily unreacted isoalkane which is recycled vialine 52 to the top of reactor 10.

FIG. 2 is a schematic, simplified illustration of the manner of positionof the disperser (segments 140 a-k) within the reactor 110. Eachdisperser segment (e.g., 140 a, 140 f, 140 g) is disposed laterallyacross the width of the reactor (preferably filling the entire width)along the length of all or a portion being less than all of the reactorin the form of multiple sheets of the disperser. Sulfuric acid isadmitted to the reactor via line 158 and a mixed stream of olefin andisoparaffin is admitted via line 116 (or multiple feeds as describedabove. The product comprising alkylate, unreacted olefin, unreactedisoparaffin and spent acid (the entire contents from the reactor) exitsthe reactor via line 118 for treatment as previously described.

The preferred disperser 200 is shown in FIG. 3 as comprising wire 205co-knit with a multi filament material 210.

Experimental Set Up for Alkylation of Isoparaffin+Olefin

For the following examples the laboratory reactor is 15 feet high by 1.5inches diameter. It is packed with varying amounts and types of packingmaterial. The H₂SO₄ inventory is about 1 liter depending on the holdupof the packing used. The surge reservoir is about 3 liters and passesall the acid plus liquid hydrocarbon out the bottom to circulate atwo-phase mixture with a single pump. Feeds are introduced at the top ofthe reactor to flow down with the recycle mixture. Vapor is produced byheat of reaction plus ambient heat gains and helps force the liquidsdown through the packing creating great turbulence and mixing. Most ofthe vapors are condensed after the reactor outlet. Uncondensed vapor andliquid hydrocarbon product passes through an acid de-entrainer thenthrough the backpressure regulator to the de-isobutanizer. Mass flowmeters are used for feed flows and a Doppler meter measures thecirculation rate. Liquid products from the de-isobutanizer are weighed.However, the vent flow rate is estimated as being the difference betweenthe mass flow metered feed in and the weighed liquid products out. GCanalyzes all hydrocarbon products, including the vent. Titration is usedfor spent acid assay.

Operation

In the following examples the experimental unit circulates hydrocarbonand acid down flow at the boiling point of the hydrocarbons present.Pressure and temperature readings are logged electronically. The reactoroutlet temperature and pressure are used to calculate the amount of iC₄in the recycle hydrocarbon using an iC₄/Alkylate flash calculation.

A backpressure regulator that passes both product liquid and vapor tothe de-isobutanizer tower, maintains the pressure. A small amount of N₂may be used primarily to keep acid from backing up into the feed line.However, too much N₂ will cause a decrease in product quality bydiluting reactive isoparaffin in the vapor phase.

The circulation pump in the experimental setup circulates both the acidemulsion layer and the liquid hydrocarbon layer. Alternatively, thesetwo phases may be pumped separately.

The acid inventory is maintained by momentarily diverting the entirerecycle through a measuring tube using a three-way valve. The trappedmaterial settles in seconds to form two layers. The volume percent acidlayer and hydrocarbon layer is then used in conjunction with the Dopplermeter reading to estimate the volumetric circulation rates of bothphases.

The DP (pressure higher at the top or reactor inlet) is maintainedbetween 0 and 3 psi by manipulating the circulation rates and the heatbalance around the unit. Different packing usually requires differentvapor and liquid flow rates to load to the same DP. Most of the time,the ambient heat gains and the heat of reaction provide adequate vapor(mostly iC₄) loading.

Because of refrigeration constraints, about 1-3 lbs/hr of extra liquidiC₄ may be introduced with the feed to provide some trim cooling. Thisexcess iC₄ is relatively small and does not significantly affect theiC₄/Olefin ratio since the circulating hydrocarbon rates are typicallyon the order of 100-200 pounds per hour. It is the circulatinghydrocarbon flow rate and composition that dominates the iC₄ ratios toeverything else.

Typical Operating Conditions for C4 Alkylation in the Examples

Feed olefin C4's Olefin in - lbs/hr 0.25-.50  Alky out - lbs/hr0.50-1.2  Rxn Temp out - F. 50-60 Rxn Psig out  6-16 DP - Psi 0.5-3.0Recycle rates: Acid phase - L/min 0.3-1   HC phase - L/min 1-3 Wt % iC4in HC recycle 75-45 Wt % H2SO4 in Spent acid 83-89 Wt % H2O in Spentacid 2-4 Fresh acid addition - lbs/gal alky 0.3-0.5 Packing Type 1 or2 - see notes below Packing Hgt in feet 10-15 Pack density lbs/ft3  5-14Notes: 1. Packing type 1 is .011 inch diameter 304 ss wire coknittedwith 400 denier multifilament fiberglass thread every other stitch. 2.Packing type 2 is .011 inch diameter alloy 20 wire coknitted with 800denier multifilament poly propylene yarn every other stitch.

Example 1

Refinery C4 Olefins used as feedstocks To the Lab Unit: 38% iB in Low iBtotal olefins methane 0.02 0.00 ethane 0.00 0.00 ethene 0.00 0.00propane 0.77 0.41 propene 0.14 0.16 propyne 0.02 0.00 propadiene 0.010.02 iso-butane 23.91 47.50 iso-butene 0.90 15.90 1-butene 20.02 10.491,3-butadiene 0.02 0.19 n-butane 22.63 10.79 t-2-butene 18.05 7.932,2-dm propane 0.09 0.00 1-butyne 0.00 0.01 m-cyclopropane 0.03 0.03c-2-butene 12.09 5.43 1,2-butadiene 0.00 0.01 3M-1-butene 0.26 0.04iso-pentane 0.98 0.02 1-pentene 0.06 0.82 2M-1-butene 0.01 0.01n-pentane 0.01 0.03 t-2-pentene 0.00 0.08 c-2-pentene 0.00 0.00t-3-pentadiene 0.00 0.08 c-1,3-pentadiene 0.00 0.00 unknowns 0.01 0.08100.00 100.00

Comparison of Refinery produced Alkylate with Lab Unit results usingsimilar low iB C4 feed Plant A Plant B Lab 1 Lab 2 iC5 6.27 2.70 2.512.78 2,3-dmb 4.05 2.84 2.80 3.02 C6 1.63 1.19 1.00 1.15 2,2,3-tmb 0.200.17 0.18 0.19 C7 7.17 5.55 4.35 4.35 TM C8 53.88 61.76 66.84 66.93 DMC8 12.27 12.47 12.69 12.44 TM C9 5.04 4.22 2.89 2.74 DM C9 0.57 1.010.29 0.18 TM C10 1.14 0.91 0.70 0.64 UNK C10 0.51 0.54 0.29 0.29 TM C110.99 0.77 0.69 0.71 UNK C11 1.09 0.02 0.00 0.00 C12 4.37 1.71 4.72 4.60C13 0.00 1.58 0.00 0.00 C14 0.03 1.57 0.05 0.00 C15 0.00 0.13 0.00 0.00HV'S 0.05 0.04 0.00 0.00 UNK 0.74 0.83 0.00 0.00 sum 100.00 100.00100.00 100.00 Av MW 113.4 116.0 114.9 114.6 Bromine no. <1 <1 <1 <1Total Sulfur ppm <10 <10 <10 <10 TOTAL % TM 61.05 67.66 71.12 71.01 TMC8/DM C8 (ratio) 4.39 4.95 5.27 5.38 TM C9/DM C9 (ratio) 8.85 4.19 10.0815.57

Typical vent analysis: wt % hydrogen 0.000 oxygen 0.124 nitrogen 3.877methane 0.019 carbon monoxide 0.000 carbon dioxide 0.000 ethane 0.000ethene 0.000 ethyne 0.000 propane 1.066 propene 0.000 propadiene 0.000iso-butane 81.233 iso-butene 0.021 1-butene 0.000 1,3-butadiene 0.031n-butane 3.398 t-2-butene 0.000 m-cyclopropane 0.000 c-2-butene 0.000iso-pentane 0.968 1-pentene 0.000 n-pentane 0.000 C5+ 0.391

Example 2

Effect of Isobutylene (iB) on Alky Quality lab 1 100% iB 38% iB low iBiC5 3.66 3.97 2.78 2,3-dmb 3.60 3.56 3.02 C6 1.42 0.52 1.15 2,2,3-tmb0.40 0.23 0.19 C7 5.27 5.08 4.35 TM C8 50.79 56.95 66.93 DM C8 11.7712.64 12.44 TM C9 6.07 4.22 2.74 DM C9 0.58 0.45 0.18 TM C10 2.06 1.330.64 UNK C10 1.14 0.67 0.29 TM C11 2.54 1.28 0.71 UNK C11 1.00 0.00 0.00C12 8.30 8.99 4.60 C13 0.07 0.00 0.00 C14 0.28 0.14 0.00 C15 0.12 0.000.00 HV'S 0.38 0.00 0.00 UNK 0.54 0.00 0.00 sum 100.00 100.00 100.00 AvMW 119.1 117.3 114.9 Bromine no. ~1 <1 <1 Total Sulfur ppm <10 <10 <10TOTAL % TM 61.46 63.77 71.12 TM C8/DM C8 4.31 4.51 5.27 TM C9/DM C910.51 9.34 10.08

Example 3

Propylene + iC4 Alkylation Sample Point product propane 0.01 iso-butane9.25 n-butane 0.32 iso-pentane 0.97 n-pentane 0.00 2,3-dm butane 2.072M-pentane 0.30 3M-pentane 0.14 n-hexane 0.00 2,4-dm pentane 15.592,2,3-tm butane 0.04 3,3-dm pentane 0.01 cyclohexane 0.00 2M-hexane 0.342,3-dm pentane 48.97 1,1-dm cyclopentane 0.00 3M-hexane 0.35 2,2,4-tmpentane 3.42 n-heptane 0.00 2,5-dm hexane 0.37 2,4-dm hexane 0.562,3,4-tm pentane 1.52 2,3,3-tm pentane 1.21 2,3-dm hexane 0.64 2,2,5-tmhexane 0.68 2,3,4-tm hexane 0.13 2,2-dm heptane 0.01 2,4-dm heptane 0.032,6-dm heptane 0.03 2,2,4-tm-heptane 1.83 3,3,5-tm-heptane 1.702,3,6-tm-heptane 1.16 2,3,5-tm-heptane 0.16 tm-heptane 1.002,2,6-trimethyloctane 2.32 C8s 0.20 C9s 0.20 C10s 0.98 C11s 1.62 C12s1.73 C13s 0.09 C14s 0.05 C15s 0.01 unknowns 0.01 heavies 0.00 100.00

Example 4

Isobutane + pentene 1 alkylation product Wt % C5 5.03 2,3-dmb 0.74 C60.35 DM C7 1.14 C7 0.17 TM C8 22.26 DM C8 3.70 TM C9 52.40 DM C9 6.72 TMC10 1.51 UNK C10 0.56 TM C11 0.16 UNK C11 0.38 C12 3.68 C13 0.33 C140.11 C15 0.08 HV'S 0.03 UNK 0.63 100.00 Avg MW 123.2 expected MW 128feed olefin #/hr 0.25 Alky product #/hr 0.47

Example 5

Oligomerization product from C4 feedstock with 38% iB in total olefins.(This product was in turn used as the olefin feed to the lab Alkylationunit) iso-butane 48.8 iso-butene + 1-butene 1.6 n-butane 11.2 t-2-butene14.3 c-2-butene 6.5 iso-pentane 1.0 t-2-pentene 0.1 unknowns 1.52,4,4-tm-1-pentene 4.7 2,4,4-tm-2-pentene 1.3 other C8's 3.4 groupedC12's 4.4 grouped C16's 1.2 100.0

Oligomerization effect on Alky products using C4 feed iB = 38% ofOlefins before after iC5 3.97 2.39 2,3-dmb 3.56 2.87 C6 0.52 1.172,2,3-tmb 0.23 0.20 C7 5.08 4.95 TM C8 56.95 58.34 DM C8 12.64 12.80 TMC9 4.22 4.15 DM C9 0.45 0.35 TM C10 1.33 1.29 UNK C10 0.67 0.57 TM C111.28 1.41 UNK C11 0.00 0.00 C12 8.99 9.41 C13 0.00 0.00 C14 0.14 0.11C15 0.00 0.00 HV'S 0.00 0.00 UNK 0.00 0.00 sum 100.00 100.00 Av MW 117.3118.3 Bromine no. <1 <1 Total Sulfur ppm <10 <10 TOTAL % TM 63.77 65.19TM C8/DM C8 4.51 4.56 TM C9/DM C9 9.34 11.75 Operating conditions:Olefin in - lbs/hr .25 .25 Alky out - lbs/hr .53 .53 Rxn Temp out - F.52.0 52.2 Rxn Psig out 12.2 11.8 DP - Psi ~1 ~1 Recycle rates: Acidphase - L/min 1.0 1.0 HC phase - L/min 2.6 2.6 % iC4 in HC recycle 69 67Packing Type 2 2 Packing Hgt in feet 15 15 Pack density lbs/ft3 7 7

Example 6

Alkylate quality from Isobutene + Isobutane or Oligomers of iB + iC4. iBDIB TIB+ IC5 3.66 3.97 3.41 2,3-dmb 3.60 3.70 3.18 C6 1.42 1.36 1.532,2,3-tmb 0.40 0.38 0.27 C7 5.27 4.96 6.39 TM C8 50.79 47.93 38.35 DM C811.77 8.92 12.91 TM C9 6.07 6.60 10.31 DM C9 0.58 0.81 1.10 TM C10 2.063.09 3.29 UNK C10 1.14 1.18 1.35 TM C11 2.54 2.53 2.72 UNK C11 1.00 1.790.00 C12 8.30 10.51 14.97 C13 0.07 0.31 0.07 C14 0.28 1.47 0.14 C15 0.120.29 0.00 HV'S 0.38 0.19 0.00 UNK 0.54 0.01 0.00 Sum 100.00 100.00100.00 Av MW 119.1 122.1 122.9 Bromine no. ~1 ~1 ~1 Total Sulfur ppm <10<10 <10 TOTAL % TM 61.46 60.15 54.67 TM C8/DM C8 4.31 5.37 2.97 TM C9/DMC9 10.51 8.15 9.37 Operating conditions: Feed olefin iB DIB TIB+ Olefinin - lbs/hr 0.25 0.40 0.25 Alky out - lbs/hr 0.49 0.78 0.48 Rxn Tempout - F. 52 51.6 51.7 Rxn psig out 13 13.5 5.7 DP - psi 2.5 1.1 ~1Recycle rates: Acid phase - L/min 0.8 0.5 1.0 HC phase - L/min 1.8 1.43.0 % iC4 in HC recycle 73 76 45 Packing Type 1 1 2 Packing Hgt in feet10 10 15 Pack density lbs/ft3 6 6 7

Example 7

Expected vs. actual alkylation product MW's and moles iC4 uptake withvarious olefins (e.g. in theory 1 mole of C6 olefin should react with 1mole of iC4 to form a C10 alkylate; MW = 142) Results indicatedepolymerization generating more and lower MW olefins that combine withadditional iC4. Moles iC4 uptake per mole Olefin fed Average product MWOlefin Expected Actual Expected Actual Hexene-1 1.0 1.2 142 129 Octene-11.0 1.4 170 135 Di-isobutylene 1.0 1.8 170 122 Tri-isobutylene+ 1.0 2.6226 123

Example 8

Isobutane + pentene 1 alkylation product Wt % IC5 5.03 2,3-dmb 0.74 C60.35 DM C7 1.14 C7 0.17 TM C8 22.26 DM C8 3.70 TM C9 52.40 DM C9 6.72 TMC10 1.51 UNK C10 0.56 TM C11 0.16 UNK C11 0.38 C12 3.68 C13 0.33 C140.11 C15 0.08 HV'S 0.03 UNK 0.63 100.00 Avg MW 123.2 expected MW 128feed olefin #/hr 0.25 Alky product #/hr 0.47

1. A combination for carrying out catalytic reactions in concurrent downflow comprising a vertical reactor and a disperser disposed in said vertical reactor as a plurality of vertically arranged, transverse mats within and across said vertical reactor, said disperser comprising at least 50 volume % open space and comprising mesh wire co-knit with a multi filament component or expanded metal intertwined with a multi filament component, said multi filament selected from inert polymers, catalytic polymers, catalytic metals or mixtures thereof.
 2. The combination according to claim 1 wherein said open space is up to about 97 volume %.
 3. The combination according to claim 1 wherein said disperser comprises a co-knit mesh of wire and polymer mesh.
 4. The combination according to claim 1 wherein said disperser comprises co-knit mesh wire and fiberglass.
 5. The combination according to claim 1 wherein said disperser comprises a mesh of co-knit wire and a multi filament component comprising polytetrafluoroethylene, steel wool, polypropylene, PVDF, polyester or combinations thereof.
 6. The combination according to claim 1 wherein said disperser comprises a structure comprising a plurality of sheets of wire mesh formed into vee shaped corrugations having flats between the vees, said plurality of sheets being of substantially uniform size having the peaks oriented in the same direction and substantially in alignment, said sheets being separated by a plurality of rigid members oriented normally to and resting upon said vees.
 7. A combination for carrying out catalytic reactions in concurrent downflow comprising a vertical reactor, a disperser disposed in said vertical reactor said disperser comprising sheets, bundles or bales of a co-knit wire and a multi filament component or combinations thereof, comprising at least one partially liquid reactant, catalyst and reaction conditions to maintain said partially liquid reactant at a boiling point.
 8. The combination according to claim 7 wherein said disperser comprises mesh wire co-knit with a multi filament component or expanded metal intertwined with a multi filament component, said multi filament selected from inert polymers, catalytic polymers, catalytic metals or mixtures thereof.
 9. A combination for carrying out catalytic reactions in concurrent downflow comprising a vertical reactor, a disperser disposed in said vertical reactor as a plurality of vertically arranged, transverse mats within and across said vertical reactor, comprising at least one partially liquid reactant, catalyst and reaction conditions to maintain said partially liquid reactant at a boiling point wherein said disperser comprises a co-knit mesh of wire and polymer mesh.
 10. A combination for carrying out catalytic reactions in concurrent downflow comprising a vertical reactor, a disperser disposed in said vertical reactor as a plurality of vertically arranged, transverse mats within and across said vertical reactor, comprising at least one partially liquid reactant, catalyst and reaction conditions to maintain said partially liquid reactant at a boiling point wherein said disperser comprises co-knit mesh wire and fiberglass.
 11. A combination for carrying out catalytic reactions in concurrent downflow comprising a vertical reactor, a disperser disposed in said vertical reactor as a plurality of vertically arranged, transverse mats within and across said vertical reactor, comprising at least one partially liquid reactant, catalyst and reaction conditions to maintain said partially liquid reactant at a boiling point wherein said disperser comprises a mesh of co-knit wire and a multi filament component comprising polytetrafluoroethylene, steel wool, polypropylene, PVDF, polyester or combinations thereof.
 12. A combination for carrying out catalytic reactions in concurrent downflow comprising a vertical reactor, a disperser disposed in said vertical reactor as a plurality of vertically arranged, transverse mats within and across said vertical reactor, comprising at least one partially liquid reactant, catalyst and reaction conditions to maintain said partially liquid reactant at a boiling point wherein said disperser comprises mesh wire or expanded metal co-knit with a multi filament catalytic material of sulfonated vinyl resin, Ni, Pt, Co, Mo, Ag or mixtures thereof.
 13. A disperser comprising mesh wire or expanded metal co-knit with a multi filament catalytic material of sulfonated vinyl resin alone or with a metal selected from the group consisting of Ni, Pt, Co, Mo, Ag or mixtures thereof. 